Separator with liquid carry-over reduction assembly

ABSTRACT

A separator which includes a vessel with a horizontal section defining a horizontal chamber and a vertical section defining a vertical chamber. The vertical section extends upwardly from the horizontal section. A tubular member is positioned in the vertical section in such a way that the tubular member provides a fluid passage between the horizontal chamber and the vertical chamber and cooperates with the vertical section and the horizontal section to define a liquid receiving space. A deflector plate is spaced from the upper end of the tubular member in such a way that fluid passing up through the tubular member is deflected into the liquid receiving space and returned to the horizontal chamber.

INCORPORATION BY REFERENCE

The entirety of U.S. patent application Ser. No. 12/465,161, filed May13, 2009; and U.S. Provisional Application Ser. No. 61/052,818, filedMay 13, 2008, are each hereby expressly incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to separators for separatingliquids and gases and/or liquids and liquids. More particularly, but notby way of limitation, the present invention relates to high-volumeseparators for removing liquids such as oil and water from natural gas.

2. Brief Description of Related Art

Separators are often used to separate liquids from gases, as well asliquids from other liquids. Some separators separate oil and gas, orwater and gas. Other separators separate oil, water and gas. When gas isseparated, it generally migrates to the top of the separator vessel dueto its relatively lower density. However, in separators processing highvolumes of liquid, and during surges in separators, liquid may not besufficiently removed from the gas, and may pass through the separator tothe gas outlet. One solution to this problem is to use a bigger vessel.However, this can be expensive.

As such, there is a perpetual need for more-efficient, more-effective,and/or less-expensive separators such as, for example, separators forremoving oil and water from gas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a separator constructed in accordance withthe present invention.

FIG. 2 is a sectional view of another embodiment of a liquid carryoverreduction assembly.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a sectional view of another embodiment of a liquid returnline.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring now to the drawings, and more particularly to FIG. 1, showntherein and designated by the reference numeral 10 is a separatorconstructed in accordance with the present invention. The exemplaryembodiment of the separator 10 shown is for high-volume separation ofoil and water from gas in such a way that the oil and water are alsoseparated from one another. Other embodiments may only separate oneliquid from a gas, or may separate multiple liquids from a gas withoutseparating the multiple liquids.

The separator 10 includes a vessel 14 having a horizontal section 18 anda vertical section 22. The horizontal section 18 of the vessel 14 ispreferably formed with an elongated, cylindrical shape, as shown, thatdefines a horizontal chamber 26. For example, the horizontal section 18of the vessel 14 may be a substantially-circular cylinder having adiameter of about 20 inches and a length of about 90 inches. Otherembodiments of the horizontal section 18 may be formed with any suitableshape such as, for example, rectangular, square, triangular, or thelike, and may be formed with any suitable dimensions. The horizontalsection 18 of the vessel 14 preferably includes an inlet 30, an inletbaffle 34, quieting baffles 38, a mist pad 42, a spillway wall 46, awall 50, a liquid-liquid weir 54, and one or more cleanouts 58. It willbe appreciated, however, that the horizontal section 18 may include avariety of components which cooperate with one another to cause liquidand gas to separate from each other. The description of the constructionand operation of the horizontal section 28 contained herein is intendedto provide an example of one arrangement of a horizontal sectionsuitable for separating liquids from gases, and is not intended to belimiting. It should be understood that a number of variations to thecomponents and the configuration of those components described hereincan be made without changing the scope of the invention set forthherein.

The vertical section 22 of the vessel 14 is preferably formed with anelongated, cylindrical shape, as shown, that defines a vertical chamber28. For example, the vertical section 22 of the vessel 14 may be asubstantially-circular cylinder having a diameter of about 16 inches anda length of about 48 inches. Other embodiments of the vertical section22 may be formed with any suitable shape such as, for example,rectangular, square, triangular, or the like, and may be formed with anysuitable dimensions. The vertical section 22 is preferably substantiallyperpendicular to the horizontal section 18, but may be angularlydisposed from the horizontal section 18 in any suitable configuration.The vertical section 22 of the vessel 14 preferably includes a liquidcarryover reduction assembly 60, a mist pad 66, and a gas outlet 70.

The inlet 30 is preferably connected to a supply pipe 98 that deliversan unseparated mixture such as, for example, gas, oil, and water (thatmay be steam) from a well head (not shown) or the like. In the preferredembodiment, the vessel 14 is preferably constructed such that the vessel14 is capable of operating at high separation rates and high internalpressures. For example, in one embodiment, the separator 10 functions atan operating pressure between about 150 psig and about 250 psig, morepreferably between about 175 psig and about 225 psig, and mostpreferably about 200 psig. In one embodiment, the separator 10 is alsopreferably capable of processing a mixture of gas, oil, and water at arate of about 4 million standard cubic feet per day (MMSCFD) of gas anda combined liquid capacity of about 800 barrels per day (bbl/d) with aretention time of about three minutes.

The operation of the separator 10 will be described herein as separatingan exemplary mixture of gas, oil, and water, in which the preferredgaseous portion is the gas and the preferred liquid portions are the oiland water. However, as will be appreciated by those skilled in the art,the separator 10 may be used to separate various mixtures having anynumber of components. As the mixture enters the separator 10 through theinlet 30, the mixture hits the inlet baffle 34. The mixture preferablyenters the separator 10 at a relatively high velocity and/or pressuresuch that when the mixture impacts the inlet baffle 34, it is forced toflow around the inlet baffle 34, as indicated by the arrows 102. As willbe appreciated by those skilled in the art, the gas portion of themixture has less resistance to changes in direction and will primarilyflow around the inlet baffle 34. In contrast, the liquid portion(s) ofthe mixture, and even the vaporized liquid portions of the mixture, havea higher mass and resulting higher resistance to changes in direction,such that at least a portion of the water and oil in the initial mixturewill impact the inlet baffle 34 and will be carried downward by gravityinto the bottom of the horizontal section 18 of the vessel 14, asindicated by the layers of oil 106 and water 110. Generally, not all ofthe liquid components of the mixture are removed by the inlet baffle 34,however, and as the mixture flows past the inlet baffle 34, the mixtureis preferably separated into a primarily-liquid mixture, e.g., oil 106and water 110, and a primarily-gaseous mixture, e.g., gas 114.

At least the primarily-gaseous mixture next flows through the quietingbaffles 38. The quieting baffles 38 are preferably constructed toencourage laminar flow of the mixture such that the flow characteristicsof the mixture preferably become smoother and more uniform and permitgravity to carry the relatively heavier components, e.g., oil and water,downward and out of the gas, as well as to permit the relatively heavierliquid, e.g., water, downward and out of the oil, as indicated by thelayers of oil 106 and water 110 shown. Various suitable configurationsfor the quieting baffles 38 are known in the art, and any functionalvariety may be used.

After passing through the quieting baffles 38, at least theprimarily-gaseous mixture flows through the mist pad 42. The mist pad 42preferably extends from the top of the horizontal chamber 26 down intothe primarily-liquid mixture such that all of the primarily-liquidmixture passes through the mist pad 42. The mist pad 42 is preferablyconstructed of a porous material such as, for example, a wire mesh,screen, sponge, or the like. The mist pad 42 operates in similar fashionto the inlet baffle 34 in that the pores of the mist pad 42 provide anonlinear path for the gas of the mixture to flow through, while theintermediate solid portions interrupt the flow of heavier portions,e.g., oil and water, of the mixture to separate these heavier portionsfrom the mixture. In one embodiment, the mist pad 42 is constructed of awire mesh material having a thickness of about six inches. In otherembodiments, the mist pad 42 may be formed of any suitable material inany suitable shape. In yet further embodiments, the mist pad 42 mayinclude any suitable number of mist pads 42, may be substituted withsimilar structures, or may be omitted entirely.

After passing through the mist pad 42, the primarily-gaseous mixtureflows from the horizontal chamber 26 into the vertical chamber 28 viathe liquid carryover reduction assembly 60. The liquid carryoverreduction assembly 60 functions to deflect liquids that may enter thevertical chamber 28 away from the gas outlet 70 and back to thehorizontal chamber 26. The liquid carryover reduction assembly 60includes a tubular member 62 and a deflector plate 74.

The tubular member 62 of the liquid carryover reduction assembly 60 ispositioned in the vertical section 22 and is connected to and extendsupwardly from the horizontal section 18 toward the upper end of thevertical section 22 in such a way that the tubular member 62 provides afluid passage between the horizontal chamber 26 and the vertical chamber28. The tubular member 62 further cooperates with the vertical section22 and the horizontal section 18 to define a liquid receiving space 64.In the present embodiment, tubular member 62 is concentricallypositioned relative to the vertical section 22 so that the liquidreceiving space 64 is substantially annular; however, it should beunderstood that the liquid receiving space 64 could take a variety offorms. For example, the liquid receiving space 64 may extend onlypartially about the tubular member 62. Also, it is contemplated that thefluid passage defined by the tubular member 62 and the liquid receivingspace 64 may be reversed such that the area between the tubular member62 and the vertical section 22 functions as the fluid passage and theinterior of the tubular member 62 functions as the liquid receivingspace 74.

A deflector plate 74 is connected to an upper end of the tubular member62 in such a way that a significant portion of the liquid carried upthrough the tubular member 62 will contact the underside of thedeflector plate 74 and will be deflected or redirected in an outward anddownward direction and will pass into the liquid receiving space 64. Theliquid will also contact the deflector plate 74 so that a portion of theliquid may be deflected back down the tubular member 62 and into thehorizontal chamber 26.

The deflector plate 74 is connected to the tubular member 62 with aplurality of connector members 76 a, 76 b, 76 c, and 76 d (best shown inFIG. 3) extending between the tubular member 62 and the deflector plate74 in a spaced apart relationship to one another so as to define atleast one opening 118 between the tubular member 62 and the deflectorplate 74.

The deflector plate 74 is shown in FIG. 1 as a flat circular platehaving a diameter greater than the diameter of the tubular member 62.FIGS. 2 and 3 illustrate another embodiment of a deflector plate 74 a.The deflector plate 74 a is a hollow dome-shaped member having a lowerannular edge 75 and a diameter greater than the diameter of the tubularmember 62. The deflector plate 74 a is preferably connected to thetubular member 62 so that the lower edge 75 of the deflector plate 74 ais positioned below the upper end of the tubular member 62. As theprimarily-gaseous mixture passes up through the tubular member 62, thedeflector plate 74 a will cause the travel path of the primarily-gaseousmixture to be redirected in an outward and downward direction. Upon theprimarily-gaseous mixture passing beyond the lower edge 75 of thedeflector plate 74 b, the gas will migrate toward the gas outlet 70causing the gas to reverse its direction in such a way that the liquid,which is heavier than the gas, to continue traveling in a downwarddirection and into the liquid receiving space 64.

While two embodiments of the deflector plate 74 and 74 a have beendepicted, it should be appreciated that the deflector plate may beformed to have a variety of shapes and configurations which function toproduce the desired result of the liquid being returned to thehorizontal chamber 26. It should be understood that the spacing anddimensions of the various components of the liquid carry-over reductionassembly 60 will vary as a function of variables such as gascomposition, temperature, pressure, gas flow rate, and anticipatedliquid carry-over volume.

The gas traveling towards the gas outlet 70 preferably continues to flowupwards and subsequently passes through the mist pad 66. The mist pad 66is preferably similar in form and function to the mist pad 42, describedabove. However, the mist pad 66 preferably spans the full width of thevertical chamber 28 such that substantially all of the gas exiting theopenings 118 of the liquid carryover reduction assembly 60 flows throughthe mist pad 66. As described above with reference to the mist pad 42,the mist pad 66 preferably removes at least a portion of any remainingliquid portions, e.g., oil and water, from the gas. The liquid portions,e.g., oil and water, collected by the mist pad 66 preferably condenseand fall downward into the liquid receiving space 64. It will beappreciated that the deflector space 74 further functions to deflectliquid falling from the mist pad 66 into the liquid receiving space 64.

A liquid return line 86 extends between the liquid receiving space 64and the horizontal chamber 26 in such a way that liquid that passes intothe liquid receiving space 64 is able to flow from the liquid receivingspace 64 to the horizontal chamber 26. Thus, as the level of liquid 122in the liquid receiving space 64 reaches the level of the liquid returnline 86, the liquid 122 preferably passes through the liquid return line86 and back into the horizontal chamber 26.

In one embodiment, a portion of the liquid return line 86 (FIG. 1) ispositioned externally relative to the vessel 14. The liquid return line86 extends from the vertical chamber 28 to the horizontal chamber 26between the fluid inlet 30 of the horizontal section 18 and the verticalintersection of the horizontal section 18 and the vertical section 22,so as to enable fluid communication between the liquid receiving space64 and the horizontal chamber 26. The liquid return line 86 preferablyincludes a check valve 90 and a shutoff valve 94. In other embodiments,either or both of the check valve 90 and the shutoff valve 94 may besubstituted, combined, omitted, or the like.

The liquid return line 86 is aligned with the quieting baffles 38 suchthat the liquid 122 from the liquid return line 86 a will preferablyfall into a relatively calm flow area and be permitted to settle intoits component parts within the horizontal chamber 26. In otherembodiments, the liquid return line 86 may be disposed in any suitablelocation, but is preferably adjacent to or downstream of the quietingbaffles 38 so as to minimize the amount of liquid returned to theprimarily-gaseous mixture.

FIG. 4 illustrates another embodiment of a liquid return line 86 a inthe form of a tubular downcomer 96. The tubular downcomer 96 provides apathway for the liquid to travel from the liquid receiving space 64 tothe horizontal chamber 26. The tubular downcomer 96 extends from theliquid receiving space 64 into the horizontal chamber 26 such that thelower end of the tubular downcomer 96 is positioned below the surface ofthe liquid passing through the horizontal chamber 26. As shown, theupper end of the tubular downcomer 96 is preferably located a relativelysmall distance above the bottom of the liquid receiving space 64 suchthat at least some portion of any solid contaminants are trapped in thebottom of the liquid receiving space 64 rather than returned with theliquid 122. As such, the vertical section 22 may be provided with adrain (not shown) to allow periodic cleaning of the liquid receivingspace 64. The position of the lower end of the tubular downcomer 96below the surface of the liquid in the horizontal chamber 26 isdesirable because it forms a liquid seal which prevents the migration ofgas up through the tubular downcomer 96.

As the liquid 122 from the liquid return line 86 returns to thehorizontal chamber 26, the liquid falls through the gas 114 andseparates into its component parts, e.g., oil and water. These componentparts then join the liquid 106 and 100 already in the horizontal section18. As shown, the density differential between the oil and waterpreferably causes the oil to migrate upward to an oil layer 106, andpreferably causes the water to migrate downward to a water layer 110below the oil layer 106. The liquid layers, e.g., 106 and 110,preferably flow toward the spillway wall 46.

The spillway wall 46 and the divider wall 50 cooperate to divide a lowerpart of the horizontal section 18 into a primary basin 126, an oil basin130, and a water basin 134. As shown, the divider wall 50 preferablyextends above the spillway wall 46 such that the top of the water basin134 extends above the top of the oil basin 130. Because the top of theprimary basin 126 and the top of the oil basin 130 are both limited bythe spillway wall 46, the tops of the primary basin 126 and oil basin130 are preferably at the same height. Additionally, the spillway wall46 is shaped to define a passageway 138 passing under the oil basin 130and under a portion of the water basin 134 as well. The liquid-liquidweir 54 is preferably cooperatively associated with the spillway wall 46to enable fluid communication between the water basin 134 and thepassageway 138. The liquid-liquid weir 54 is also preferably adjustablein functional height, or the distance the liquid-liquid weir 54 extendsabove the spillway wall 46, such that the flow therethrough may beadjusted as necessary to achieve desirable functional characteristics.

As oil flows over the spillway wall 46 into the oil basin 130, waterwill flow under the spillway wall 46 and through the passageway 138.When the uppermost level of oil is above the top of the liquid-liquidweir 54, water is forced through the liquid-liquid weir 54 and into thewater basin 134. Depending on a number of factors, such as for example,the relative amounts of oil and water, the flow rate of the mixture intothe separator 10, and the like, the height of the liquid-liquid weir 54may be, and preferably is, selectively adjusted to ensure that the oiland water are effectively separated as described. For example, theheight of the liquid-liquid weir 54 is preferably such that the level ofwater layer 110 is substantially maintained above the passageway 138 sothat oil is prevented from passing into the passageway 138 or throughthe liquid-liquid weir 54. Similarly, the level of the water layer 110is preferably maintained below the top of the spillway wall 46 such thatwater is substantially prevented from flowing into the oil basin 130.

The horizontal section 18 preferably further includes an oil outlet 142,an oil sensor 146, a water outlet 150, and a water sensor 154. The oiloutlet 142 preferably includes an uptake pipe 158 and a valve 162. Asshown, the uptake pipe 158 of the oil outlet 142 preferably extends intothe oil basin 130 such that the oil in the oil basin 130 will cover alower part of the uptake pipe 158. The oil sensor 146 is preferably incommunication with the valve 162 and disposed at least partially withinor adjacent to the oil basin 130 such that as the oil basin 130 fills,the oil sensor 146 will sense the rising level of oil, or will sensewhen the oil reaches a threshold level, and will signal or otherwisecause the valve 162 to open and permit oil to flow out of the oil basin130 and out of the separator 10. For example, in one embodiment, the oilsensor 146, or a portion thereof, is disposed within or through the sideof the horizontal section 18, such that a portion of the oil sensor 146extends into the oil basin 130. In other embodiments, the oil sensor 146may be an optical, thermal, infrared, magnetic, or other sensor than iscapable of registering the level of oil in the oil basin, or is capableof registering a change in the level of oil in the oil basin 130, withor without any portion of the oil sensor 146 being disposed within theoil basin 130. Conversely, when oil in the oil basin 130 falls below thethreshold level or falls faster than the threshold rate, the oil sensor146 preferably signals or otherwise causes the valve 162 to close. Inother embodiments, it is desirable for the oil sensor 146 to sense morethan just the level of oil within the oil basin 130. For example, theoil sensor 146 may sense the undesirable presence of water within theoil reservoir 130, may sense the buildup of solid contaminants, or thelike, and may alert an operator of such negative characteristics, forexample, so the separator 10 may be shut down, cleaned, adjusted, orrepaired.

Similarly, the water outlet 150 preferably includes an uptake pipe 166and a valve 170, with the uptake pipe 166 preferably extending into thewater basin 134 such that the water in the water basin 134 will cover alower part of the uptake pipe 166. The water sensor 154 is preferablysimilar in construction, function, disposition, and mounting to the oilsensor 146, provided, however, that the water sensor is positioned tomeasure or register the level of water in the water basin 134, such thatwhen the water in the water basin 134 reaches a threshold level or risesat a threshold rate, the valve 170 of the water outlet 150 opens andpermits water to flow out of the water basin 134 and out of theseparator 10. As described above for the oil outlet 142, when the waterlevel in the water basin 134 falls below the threshold level or fallsfaster than the threshold rate, the water sensor 154 preferably signalsor otherwise causes the valve 170 to close. As will be appreciated bythose of ordinary skill in the art, the oil and water exiting the oiland water outlets 142 and 150, respectively, is preferably transferredby pipe, conduit, or the like into tanks or pipelines for storage,transportation, or use.

While various embodiments of the present invention are described herein,changes may be made in the embodiments of the invention describedherein, or in the parts or the elements of the embodiments describedherein, or in the steps or sequence of steps of the methods describedherein, without departing from the spirit and/or the scope of theinvention.

What is claimed is:
 1. A separator, comprising: a vessel including a horizontal section defining a horizontal chamber and a vertical section positioned above the horizontal chamber and defining a vertical chamber, the horizontal section having a fluid inlet for receiving a fluid including gas and at least one liquid and at least one liquid outlet for discharging liquid from the horizontal chamber, the vertical section having a gas outlet for discharging gas from the vertical chamber; a tubular member extending from the horizontal chamber and into the vertical chamber in such a way that the tubular member provides a fluid passage between the horizontal chamber and the vertical chamber and at least a portion of the tubular member and at least a portion of the vertical section cooperate to define a liquid receiving space between the tubular member and the vertical section; a deflector plate positioned above an upper end of the tubular member in such a way that liquid passing up through the tubular member is deflected into the liquid receiving space while gas is allowed to pass to the gas outlet; and a liquid return line extending from the liquid receiving space to the horizontal chamber in such a way that liquid which passes into the liquid receiving space is able to flow from the liquid receiving space to the horizontal chamber.
 2. The separator of claim 1, wherein the tubular member is positioned concentrically in relation to the vertical section.
 3. The separator of claim 2, wherein the liquid receiving space is annular.
 4. The separator of claim 1, wherein the deflector plate is substantially flat and has a diameter greater than the diameter of the tubular member.
 5. The separator of claim 1, wherein the deflector plate is dome-shaped and has a diameter greater than the diameter of the tubular member.
 6. The separator of claim 5, wherein the deflector plate has a lower edge positioned below the upper end of the tubular member.
 7. The separator of claim 1, wherein at least a portion of the return line is positioned externally relative to the vessel.
 8. The separator of claim 7, wherein the liquid return line intersects the horizontal section between the fluid inlet of the horizontal section and the vertical section.
 9. The separator of claim 8, further comprising a mist eliminator positioned downstream of the intersection of the liquid return line and the horizontal section and upstream of the vertical chamber.
 10. The separator of claim 1, further comprising a mist pad positioned between the deflector plate and the gas outlet.
 11. The separator of claim 1, wherein the liquid return line extends from the liquid receiving space into the horizontal chamber such that a lower end of the liquid return line is positioned below the surface of the liquid passing through the horizontal chamber.
 12. A separator, comprising: a horizontal section defining a horizontal chamber and having a fluid inlet for receiving a fluid including gas and at least one liquid outlet for discharging liquid from the horizontal chamber; a vertical section extending upwardly from the horizontal section and defining a vertical chamber, the vertical section having a gas outlet for discharging gas from the vertical chamber; a tubular member extending from the horizontal chamber and into the vertical chamber in such a way that the tubular member provides a fluid passage between the horizontal chamber and the vertical chamber and at least a portion of the tubular member and at least a portion of the vertical section cooperate to define a liquid receiving space between the tubular member and the vertical section; a deflector plate positioned in the vertical chamber such that liquid passing from the horizontal chamber to the vertical chamber is deflected downwardly into the liquid receiving space while gas is allowed to pass to the gas outlet; and a liquid return line extending between the liquid receiving space and the horizontal chamber in such a way that liquid that passes into the liquid receiving space is able to flow from the liquid receiving space to the horizontal chamber.
 13. The separator of claim 12, wherein at least a portion of the return line is positioned externally relative to the horizontal section and the vertical section.
 14. The separator of claim 12, wherein the liquid return line intersects the horizontal section between the fluid inlet of the horizontal section and the vertical section.
 15. The separator of claim 14, further comprising a mist eliminator positioned downstream of the intersection of the liquid return line and the horizontal section and upstream of the vertical chamber.
 16. The separator of claim 12, further comprising a mist pad positioned between the deflector plate and the gas outlet.
 17. The separator of claim 12, wherein the liquid return line extends from the liquid receiving space into the horizontal chamber such that a lower end of the liquid return line is positioned below the surface of the liquid passing through the horizontal chamber.
 18. A separator, comprising: a vessel including a horizontal section defining a horizontal chamber and a vertical section defining a vertical chamber, the vertical section extending upwardly from the horizontal section, the horizontal section having a fluid inlet for receiving a fluid including gas and at least one liquid and at least one liquid outlet for discharging liquid that separates from the gas in the horizontal chamber, the vertical section having a gas outlet at an upper end thereof for discharging gas from the vertical chamber; a tubular member positioned in the vertical section in such a way that the tubular member provides a fluid passage between the horizontal chamber and the vertical chamber, at least a portion of the tubular member cooperating with at least a portion of the vertical section and at least a portion of the horizontal section to define a liquid receiving space; a deflector plate positioned above an upper end of the tubular member in such a way that liquid passing up through the tubular member is deflected into the liquid receiving space while gas is allowed to pass to the gas outlet; and a liquid return line extending between the liquid receiving space and the horizontal chamber in such a way that liquid which passes into the liquid receiving space is able to flow from the liquid receiving space to the horizontal chamber, the liquid return line extending vertically from the liquid receiving space into the horizontal chamber such that a lower end of the liquid return line is positioned below the surface of the liquid passing through the horizontal chamber.
 19. A separator, comprising: a horizontal section defining a horizontal chamber, the horizontal section having a fluid inlet for receiving a fluid including gas and at least one liquid and the horizontal section having at least one liquid outlet for discharging liquid from the horizontal chamber; a vertical section extending upwardly from the horizontal section and having a gas outlet, the vertical section having a fluid passage between the horizontal chamber and the vertical chamber and a liquid receiving space; a deflector plate positioned in the vertical chamber such that liquid passing from the horizontal chamber to the vertical chamber is deflected away from the gas outlet and into the liquid receiving space while gas is allowed to pass to the gas outlet; and a liquid return line extending between the liquid receiving space and the horizontal chamber in such a way that liquid which passes into the liquid receiving space is able to flow from the liquid receiving space to the horizontal chamber, the liquid return line extending vertically from the liquid receiving space into the horizontal chamber such that a lower end of the liquid return line is positioned below the surface of the liquid passing through the horizontal chamber. 